Parametric Instability of Plasma Caused by the Influence of an External High‐Frequency Electric Pumping Field

ABSTRACT In this paper, we experimentally investigated the parametric instability of magnetized plasma caused by the action of an external high‐frequency electric pumping field in the frequency range ( are the ion and electron langmuir frequencies of the plasma, is the frequency of the external high‐frequency electric field), which corresponds to the excitation of lower‐hybrid electron and ion oscillations propagating almost across the magnetic field. It has been established that the longitudinal (along the magnetic field) limitation of the plasma volume under certain conditions is a decisive factor determining the threshold characteristics of the parametric process in the lower hybrid frequency range. The given estimates indicate the need to take this factor into account in the practical use of plasma systems based on high‐frequency discharges.